Additives and lubricant formulations having improved antiwear properties

Abstract

Lubricated surfaces, lubricant compositions for lubricating a surface, and methods for increasing antiwear properties in lubricants. The lubricated surface is provided by a lubricant composition including a base oil of lubricating viscosity, at least one metal salt of phosphorothioic acid, and an amount of at least one hydrocarbon soluble titanium compound effective to provide an increase in antiwear properties of the lubricant composition. A ratio of titanium metal to phosphorus in the antiwear agent ranges from about 0.3:1 to about 1.5:1.

1. A lubricated surface comprising a lubricant composition including a base oil of lubricating viscosity, at least one metal salt of phosphorothioic acid, and an amount of at least one hydrocarbon soluble titanium compound comprising a reaction product of a titanium alkoxide and a carboxylic acid selected from the group consisting of a non-linear carboxylic acid and a carboxylic acid having more than 22 up to 25 carbon atoms, said titanium compounds being effective to provide an increase in antiwear properties of the lubricant composition wherein a weight ratio of titanium metal provided by the hydrocarbon soluble titanium compound to phosphorus in the antiwear agent ranges from about 0.3:1 to about 1.5:1. 
     
     
       2. The lubricated surface of  claim 1 , wherein the lubricated surface comprises and engine drive train. 
     
     
       3. The lubricated surface of  claim 1 , wherein the lubricated surface comprises an internal surface or component of an engine selected from the group consisting of an internal combustion engine and a compression ignition engine. 
     
     
       4. The lubricated surface of  claim 1 , wherein the amount of hydrocarbon soluble titanium compound provides an amount of titanium ranging from about 10 ppm to about 1000 ppm in the lubricant composition. 
     
     
       5. The lubricated surface of  claim 1 , wherein the amount of hydrocarbon soluble titanium compound provides an amount of titanium ranging from about 50 ppm to about 800 ppm in the lubricant composition. 
     
     
       6. The lubricated surface of  claim 1 , wherein the hydrocarbon soluble titanium compound is substantially devoid of phosphorus and sulfur atoms. 
     
     
       7. The lubricated surface of  claim 1 , wherein the carboxylic acid comprises a mono-carboxylic acid containing at least about 6 carbon atoms and having a secondary, or tertiary carbon adjacent to a carboxyl group. 
     
     
       8. The lubricated surface of  claim 1 , wherein metal salt of phosphorothioic acid comprises zinc dihydrocarbyl dithiophosphate. 
     
     
       9. The lubricated surface of  claim 1 , wherein the lubricant composition comprises from about 200 to about 500 ppm phosphorus. 
     
     
       10. A vehicle having moving parts and containing a lubricant for lubricating the moving parts, the lubricant comprising an oil of lubricating viscosity, a friction modifier, and an antiwear agent comprising an amount of at least one hydrocarbon soluble titanium compound comprising a reaction product of a titanium alkoxide and a carboxylic acid selected from the group consisting of a non-linear carboxylic acid and a carboxylic acid having more than 22 up to 25 carbon atoms, and an amount of at least one metal salt of phosphorothioic acid, wherein a weight ratio of titanium metal provided by the hydrocarbon soluble titanium compound to phosphorus in the antiwear agent ranges from about 0.3:1 to about 1.5:1 and the antiwear agent provides a antiwear film thickness that is greater than a film thickness provided by the titanium compound or phosphorus compound alone. 
     
     
       11. The vehicle of  claim 10 , wherein the weight ratio of titanium metal to phosphorus in the antiwear agent ranges from about 0.5:1 to about 1.45:1. 
     
     
       12. The vehicle of  claim 10 , wherein the moving parts comprise a heavy duty diesel engine. 
     
     
       13. The vehicle of  claim 10 , wherein the lubricant composition comprises from about 100 to about 900 ppm phosphorus. 
     
     
       14. A fully formulated lubricant composition comprising a base oil component of lubricating viscosity, and an antiwear agent comprising an amount of hydrocarbon soluble titanium-containing compound comprising a reaction product of a titanium alkoxide and a carboxylic acid selected from the group consisting of a non-linear carboxylic acid and a carboxylic acid having more than 22 up to 25 carbon atoms, and an amount of at least one metal salt of phosphorothioic acid, wherein a weight ratio of titanium metal provided by the hydrocarbon soluble titanium compound to phosphorus in the antiwear agent ranges from about 0.3:1 to about 1.5:1. 
     
     
       15. The fully formulated lubricant composition of  claim 14 , wherein the weight ratio of titanium metal to phosphorus in the antiwear agent ranges from about 0.5:1 to about 1.45:1. 
     
     
       16. The fully formulated lubricant composition of  claim 14 , wherein the lubricant composition comprises from about 10 to about 1000 ppm titanium. 
     
     
       17. The lubricant composition of  claim 14  wherein the lubricant composition comprises a low ash, low sulfur, and low phosphorus lubricant composition suitable for compression ignition engines such that the finished oil contains about 0.7 wt % or less sulfur and about 0.1 wt % or less phosphorus. 
     
     
       18. A method for increasing an antiwear film thickness adjacent to a lubricated surface, comprising contacting the surface with a lubricant composition comprising a base oil of lubricating viscosity and an amount of an antiwear agent comprising a hydrocarbon soluble titanium compound comprising a reaction product of a titanium alkoxide and a carboxylic acid selected from the group consisting of a non-linear carboxylic acid and a carboxylic acid having more than 22 up to 25 carbon atoms, and a metal salt of phosphorothioic acid, wherein the antiwear agent has a titanium metal to phosphorus ratio by weight that provides a synergistic increase in the antiwear film thickness compared to an antiwear film thickness provided by a lubricant composition containing only one of the titanium compound and the metal salt of phosphorothioic acid. 
     
     
       19. The method of  claim 18 , wherein the weight ratio of titanium metal provided by the hydrocarbon soluble titanium compound to phosphorus in the antiwear agent comprises from about 0.3:1 to about 1.5:1. 
     
     
       20. The method of  claim 18 , wherein the lubricant composition further comprises a friction modifier selected from the group consisting essentially of an organomolybdenum friction modifier, a glycerol ester friction modifier, and a mixture thereof. 
     
     
       21. An additive concentrate for a lubricant composition comprising an antiwear agent including at least one metal salt of phosphorothioic acid, and an amount of at least one hydrocarbon soluble titanium compound comprising a reaction product of a titanium alkoxide and a carboxylic acid selected from the group consisting of a non-linear carboxylic acid and a carboxylic acid having more than 22 up to 25 carbon atoms, said titanium compounds being effective to provide an increase in antiwear properties of the lubricant composition, wherein a weight ratio of titanium metal provided by the hydrocarbon soluble titanium compound to phosphorus in the antiwear agent ranges from about 0.3:1 to about 1.5:1. 
     
     
       22. The additive concentrate of  claim 21 , wherein the amount of hydrocarbon soluble titanium compound provides an amount of titanium ranging from about 50 ppm to about 800 ppm in the lubricant composition. 
     
     
       23. The additive concentrate of  claim 21 , wherein an amount of the metal salt of phosphorothioic acid in the additive concentrate is sufficient to provide the lubricant composition with from about 100 to about 900 ppm phosphorus.